Composition and variation of a bird community at El Tunal Reservoir, Salta, Argentina

Abstract

In this study, we describe the species and trophic composition, and abundance and variation of bird species, during 2005 and 2006, in Tunal Reservoir, Salta. This wetland is built on the Juramento River at 25°14’S 64°31’W and it covers 3474 ha at its highest level. It is located in a degraded Chaco environment. We marked three sites with five transects (500 x 50 m) in each. We sampled these transects twice during each season, for a year, with a total of 120 samples. We analyzed the avifauna based on: Relative Abundance, Relative Importance Index, Shannon-Wiener Index and Abundance Rank Curve. We recorded 101 species from 38 families. Of all the species, 32 are migrants (seven are Neartic-Neotropical migrants and 25 are Regionals). Two bird assemblages were the most representative; those that foraged in the vegetation and those that looked for food while walking. Due to yearly water level fluctuations, that affect resource availability, variations in the composition of the bird community may be caused mainly by migratory species from the northern hemisphere.